Cryogenics is the production and behaviour of materials at very low temperatures. It isn't well defined at what point on the temperature scale refrigeration begins and cryogenics begins, but it is thought that a gas is cryogenic if it can be liquified at or below -150ºC and that cryogenics occurs below -180ºC as this is the boiling points of the permanent gases ( more

Cryogenics is the production and behaviour of materials at very low temperatures. It isn't well defined at what point on the temperature scale refrigeration begins and cryogenics begins, but it is thought that a gas is cryogenic if it can be liquified at or below -150ºC and that cryogenics occurs below -180ºC as this is the boiling points of the permanent gases (helium, hydrogen, nitrogen, oxygen and neon). Cryogenics use the Kelvin or Rankine temperature scale as they measure from absolute zero, rather than Celsius or Fahrenheit that have their zeros at arbitrary temperatures.